As is generally known, various electric components are installed in a vehicle or the like. Power and signal currents are supplied to these electric components through a wiring harness.
The wiring harness is a tube that ties a plurality of electric wires. Various wiring harnesses are used corresponding to applications or locations. For example, a flexible flat cable in which a plurality of wiring conductors are arranged in parallel is used for connecting electric components in a vehicle door on which a power window motor, a door lock unit, a switch unit, an automatic door open/close unit and the like are installed.
Travel distance of the wiring harness for the door or the like is large due to the open/close of the door. Therefore, when the door is closed, a slack is generated in the wiring harness and may be caught between the vehicle body and the door and damaged. An example of a conventional wiring harness slack absorbing device 50 for solving such a problem is shown in FIG. 6.
As shown in FIG. 6, the slack absorbing device 50 includes: a wiring harness 25; a case 30 having a case body 31 and a cover 37; and a slack absorbing unit 12 received in the case 30.
A so-called flat wiring harness such as a flexible flat cable (FFC) is used as the wiring harness 25. The case body 31 is a horizontally rectangular box having an opening. A harness outlet 35 is mounted on a rear wall of the case body 31. A not-shown harness inlet is mounted on a sidewall perpendicular to the rear wall. Namely, the outlet 35 and the inlet are disposed perpendicular to each other. The wiring harness 25 is led into the case 30 through the inlet, and led out of the case 30 through the outlet 35.
The cover 37 covers the opening of the case body 31. A not-shown locking piece is formed on a frame of the case body 31. A not-shown locking projection is formed on a frame 38 of the cover 37. By engaging the locking piece with the locking projection, the cover 37 is attached to the case body 31.
The slack absorbing unit 12 includes a seat member 13, a guiding pin 27, a compressed coil spring 23, and a harness roller 15. The guiding pin 27 is arranged in a longitudinal direction of the case body 31. One end of the guiding pin 27 is fixed to the rear wall of the case body 31.
The compressed coil spring 23 is installed to cover the guiding pin 27 and to push the wiring harness 25 toward the case 30. The harness roller 15 has a trunk to be attached to the guiding pin 27. The harness roller 15 is allowed to reciprocally move in a direction to pulling in/out the wiring harness 25 rolled in a U-shape thereon.
Thus, a slack 26 of the wiring harness 25 is pulled into or out of the case 30 accompanying the open/close of the door or the like. Therefore, the wiring harness 25 is constantly strained and the damage of the caught slack 26 is prevented.